The oldest alliance of evangelical Christians in the world has weighed in on the controversy over Rob Bell and his new book on heaven and hell.

Calling for a debate characterized by respect, humility and grace, the U.K.-based Evangelical Alliance acknowledged Bell's "brilliant communication" skills and passion to make God's love known.

But what Bell presents in Love Wins: A Book About Heaven, Hell, and the Fate of Every Person Who Ever Lived is confusing and unclear, the alliance said.

"I can see now why people are asking whether Rob Bell is a universalist (all will be saved in the end) or not, because it's unclear," Derek Tidball, a member of the Alliance's Board and Council, said in his review Tuesday. "Brilliant communication sometimes gets in the way.

"The book contains volleys of rapid-fire questions but isn't so good at giving answers, at least not clear ones."

In Love Wins, which is No. 2 on The New York Times Best Sellers list and sparked wide debate even before its release this month, Bell raises numerous questions about Jesus, salvation and eternal life that many likely hold.

"If there are only a select few who go to heaven ... how does a person end up being one of the few?" Bell, pastor of Mars Hill Bible Church in Grand Rapids, Mich., asks.

"Is it what you say or what you are that saves you? ... or who we forgive, or whether we do the will of God, or if we 'stand firm' or not?"

As the Evangelical Alliance noted, Bell does not state "dogmatically" that all will be saved in the end.

But he leaves the question open: Will everybody be saved, or will some perish apart from God forever because of their choices? ... We don't need to resolve them or answer them because we can't, and so we simply respect them."

The popular author also casts doubt on the traditional Christian understanding of hell and the fate of non-Christians, the alliance pointed out.

And "Bell appears to adopt a view more akin to 'wider hope' theology which is optimistic that God will ultimately save the vast majority of people, even, perhaps, all people."

In the book, Bell calls the dominant Christian story that only a few Christians will be called to heaven while the rest spends forever in punishment in hell "misguided and toxic." He criticizes churches that singularly preach that those who don't believe in Jesus will go to hell and questions the belief that salvation comes simply through confession, repentance and accepting Jesus.

Historically speaking, the Evangelical Alliance noted that this type of theological debate is not new. What's bringing it back into the spotlight, however, is Bell's personal profile – as a popular speaker and already best-selling author of such books as Velvet Elvis and Sex God.

"Much of what he says about the cross is straight out of the Bible. His criticism of some evangelicals for their superficial and misplaced judgmentalism rings true. He's right: biblical teaching on heaven and 'the age to come' is misrepresented if all it does is encourage some to boast, 'I've got a ticket to heaven'. The Bible presents Christ's work as much wider than the salvation of a few individuals. It is about the restoration and renewal of a fallen creation. Eternal life doesn't start 'when we die but is about a quality of life lived now'. Amen to that."

But, Tidball added, the book only presents half the truth.

And that is "disturbing to those who believe in the other half of the truth," he said.

"His teaching on hell ducks some hard issues while firing out a lot of questions of his own. God's wrath, and his holiness, is touched on only very inadequately and insubstantially," he highlighted. "He says the sacrificial understanding of the cross belongs to a primitive cultural world we no longer inhabit, so he sidesteps a key understanding of the cross."

Tidball, former principal of London School of Theology, called Bell's writing "theology-lite" and "very postmodern," with much of the book filled with "moving stories and ever-lengthening lists of questions" that would "bedazzle" listeners.

"[T]hose who wish to criticize this book need to earn the right to do so by being as passionate about sharing Christ's love as Bell himself is," he said.

The Evangelical Alliance was founded in 1846 and serves evangelical Christians in the U.K. On the nature of hell, the alliance explicitly rejects universalism and finds arguments on second chance repentance unconvincing.

The alliance is open to "wider hope" for those who have never heard the gospel, children who die in infancy (including the unborn), and those whose mental incapacity makes profession of faith in Christ impossible. But it "is insistent that absolutist assertions that these and other categories of non-professing people are saved risk being at least as arrogant as absolutist assertions that they are damned. The destiny of such people is God's to determine, and it is determined by his grace alone."